Conventionally, decoloring devices have a decoloring function of erasing printed information, such as text and images. Such a device scans and stores the text and images formed on a sheet in an electronic data format, and the text and images formed on the sheet are erased, based on the stored electronic data. The sheets that have been subject to erasing are sorted into either a tray for reusable paper or a tray for paper that has been determined to be reused.
However, problem is that, when one side of a sheet with images printed on both sides thereof cannot be successfully subject to erasing, there is no consistency in whether the reusable or non-reusable side is sorted and stacked facing up or down, which is annoying for users.